Retrievable closed cell intracranial stent for foreign body and clot removal

Abstract

Objective: To assess the technical feasibility of using a retrievable, closed cell intracranial stent delivered through a microcatheter for safe removal of foreign bodies or clot.

Methods: In vitro and in vivo testing were performed to demonstrate the feasibility of using retrievable intracranial stents for foreign body or clot removal. In vitro testing was performed in an anatomically correct silicone vascular replica by partially deploying the stent around a coil, then retracting the stent into the microcatheter to trap the coil. Withdrawal of the stent delivery system into the guide catheter resulted in coil removal. Subsequently, the technique was evaluated in a porcine model of intracranial aneurysms, wherein both fresh clot and herniated coils were extracted from the carotid arteries.

Results: In these experimental procedures, both herniated coils and fresh clot were safely and easily removed from the in vitro and in vivo models. No periprocedural adverse events were observed.

Conclusion: These in vitro and in vivo studies suggest the potential use of retrievable stents for the removal of foreign bodies or clot from the intracranial circulation.

FIGURE 1

A, coil deployed into the superior division of the right middle cerebral artery. B, stent partially deployed distal to the coil. C, captured coil being retrieved, leading to capture within the guide catheter (D).

FIGURE 2

A, two coil loops (arrowheads) herniating into the left common carotid artery (CCA) and coil. Coil mass within contralateral aneurysm (open arrow). B, placement of microcatheter tip at the level of the coil (open arrow). Partial deployment of the stent; depicted are the distal markers (black arrow). White arrow indicates the positioning marker that indicates the final point for stent retrieval. Note that the second coil had been retrieved previously using the same technique and device. C and D, captured coil loop being removed by pulling back the system. E, final control angiography with mild vasospasm at the former site of vascular clips placed surgically for temporary aneurysm construction. F, macroscopic image of captured and unraveled coil loops (curved arrow) trapped within the stent distal markers (arrows) and microcatheter (double arrow). Note the stent delivery wire (open arrow).

FIGURE 3

A, coiled aneurysm of the right CCA. Clot formation within the artery adjacent to the coil mass. B, placement of microcatheter tip into the clot. Partial deployment of the stent; depicted are the distal markers (black arrow). White arrow indicates the positioning marker (see also Fig. 1). C, complete removal of clot mass with reconstitution of blood flow. Arrow indicates mild residual vasospasm. D, macroscopic view of captured clot within the stent struts.